Question

Find the differential equation of system of concentric circles with centre (1, 2).

Answer 1

Family of concentric circles with centre (1, 2) and radius ‘r’ is (x – 1)² + (y – 2)² = r²

Differentiating both sides w.r.t., x we get

`2(x - 1) + 2(y - 2) "dy"/"dx"` = 0

⇒ `(x - 1) + (y - 2) "dy"/"dx"` = 0

Which is the required equation.